For the first time in a generation, the staunchly Republican state of Alabama has elected a Democrat. Voters turned against controversial former judge, Roy Moore, who had the endorsement of Donald Trump despite being accused of sexual assault, and backed former Prosecutor, Doug Jones.

Voters in the Sydney seat of Bennelong go to the polls this weekend in a by-election resulting from the sitting member, John Alexander being found to be a British citizen. He's recontesting the seat, up against former NSW Labor Premier, Kristina Keneally. If the Coalition loses the seat, it will also lose its majority in parliament.

Investors in online currency bitcoin have been laughing all the way to the bank in recent weeks, with the coins now fetching just shy of $20,000. And this week two major Wall Street exchanges opened trading on the coins. But there are fears the bitcoin bubble will burst.

US President Donald Trump has pledged to send astronauts back to the Moon, as the first step in a manned mission to Mars and beyond. Brad Tucker, an astrophysicist with the Australian National University, joins 7.30 from Washington DC to discuss the development.

Iraq's prime minister has declared that Islamic State has been defeated in his country after three years of combat. Former army chief Peter Leahy joins 7.30 to discuss this and the threat still posed by IS.